DESCRIPTION: This is a research development/planning grant application to initiate collaborative studies with investigators at Bilkent University in Turkey to study the genetics of Essential Tremor. Essential Tremor (ET) is one of the most common neurological diseases, with an estimated 7 million affected individuals in the United States. The most characteristic clinical feature of ET is a kinetic tremor in the hands or arms, which early in the disease process is mild. As the disease progresses, tremor becomes more severe and more anatomically widespread (e.g., head, trunk). Aside from tremor, patients with ET may also present with other motor features including gait ataxia. Non-motor features can include psychiatric manifestations, cognitive decline and dementia. Despite its extraordinarily high prevalence the genetic causes of ET are largely unknown. We propose to develop a genetic study of ET focusing on consanguineous families in Turkey. Turkey with a population of about 70 million has a high rate of consanguineous marriages. The rate of consanguinity is estimated to be as much as 20-25% with approximately 70% of all consanguineous marriages involving first cousins. Studying the genetics of ET in the Turkish population, particularly in large consanguineous families may identify novel genetic causes of ET that are also relevant to ET populations in the US and worldwide. The proposed research has a high probability of success with our collaborators, Drs Ozcelik and Tekinay's expertise in human genetics and functional studies together with an established resource of large consanguineous ET families. The specific aims of this planning grant are to: (1) further develop and solidify collaborations with the team in Bilkent and define the scope of the research that will be the focus of an R01 application; (2) assess the Bilkent team's resources and needs in order to successfully conduct the research; (3) implement cross-training between the U.S. and Turkish groups in the areas of human genetics, genetic epidemiology and risk factor assessment, genomics, clinical diagnosis, functional studies and personalized genomic medicine; and (4) conduct pilot studies to generate preliminary data necessary for an R01 application.